1. Field of the Invention
The invention relates to the structure of refrigeration cabinets as well as those devices and methods used to retain heating elements such as warm refrigerant tubing at a desired location within such cabinets.
2. Description of the Related Art
It is typical for the refrigerator and freezer compartments of refrigerators to leak small amounts of cold air around and through the gasket seals for the doors. When this leakage occurs, condensation or xe2x80x9csweatingxe2x80x9d results on the cabinet surface near the seals. It is desirable to prevent or reduce this condensation as much as possible, and various solutions have been employed to do so. For example, small heating units have been disposed inside the refrigerator cabinets and can be selectively actuated to evaporate the condensation. Unfortunately, this solution reduces the efficiency of the refrigerator since extra energy is required to operate the heating units. An alternative solution is that of running the tubing that carries warm refrigerant fluid (sometimes referred to as the post condenser loop or xe2x80x9cPC loopxe2x80x9d) within the cabinet near the areas where condensation tends to collect. The heat from the refrigerant fluid evaporates the condensation without decreasing the efficiency of the refrigerator.
One area in which improvement is desired is that of properly retaining the heating element (most typically the post condenser loop) in place at the front portions of the refrigerator cabinet. Oftentimes, separate connectors or fasteners are used. An example of this method of retaining the heating element is found in U.S. Pat. No. 4,881,315 issued to Powell et al. Powell describes clip-type retainer members that are removably affixed to portions of the refrigerator wrapper. However, the use of additional connectors or components to retain the heating element is undesirable as the part count required to assemble the refrigerator is increased and, thus, production costs are increased as well.
In many conventional refrigerator designs, the refrigerator""s exterior wrapper is joined to the interior plastic liner using a U-shaped channel (also called a triple-flange) that is rolled behind the front face panel of the wrapper. An end piece of the plastic liner is inserted into the U-shaped channel. PC loop tubing was routed adjacent to or through the rolled channel and secured therein only by the insertion of the liner. Conductive contact between the tubing and the front panel of the wrapper is not guaranteed, and without such conductive contact, heat from the PC loop can be undesirably transmitted into the refrigerated compartments of the refrigerator. In designs where the tubing has been routed adjacent the rolled channel, the position of the tubing is controlled by the geometry of the rolled form. An example of this type of arrangement is found in U.S. Pat. No. 5,255,531 issued to Williams et al. which teaches a clamping technique for retaining a hot gas tube in contact with the front wall rear surface of a refrigeration cabinet. The rolled geometry can positively position the tubing, but it also provides a path for heat to be transmitted back toward the interior compartments of the refrigerator. This is undesirable since the transmitted heat can reduce the effectiveness of cooling the interior compartments.
It would be desirable to have devices and methods that address the problems of the prior art.
The invention describes methods and devices for retaining warm refrigerant tubing within a refrigerator wrapper. Semispherical raised dimples are formed upon a gripping panel in a rolled triple flange. The dimples are intermittently positioned along the retaining panel and maintain the warm refrigerant tubing in intimate surface contact with the exterior surface panel of the refrigerator. The raised dimples preclude significant intimate surface contact between the retaining panel and the tubing and permit insulating foam to be disposed between the two so that heat recirculation to the interior of the refrigerator is minimized.
A dimpled flange arrangement is also used to retain tubing within a mullion that separates the freezer of the refrigerator from the fresh food compartment. In a preferred embodiment, a sheet metal insert is formed having two retaining panels with raised dimples thereupon that maintain the tubing in intimate surface contact with the exterior surface panel that forms the facing for the mullion.
Both the triple flange and the sheet metal insert are preferably formed by rollforming of sheet metal, and the dimples are formed during this process by pins on a roller that contact and deform a portion of the sheet metal. The use of dimples is also advantageous in that it provides an easily recognizable feature that can be used to secure the tubing within the refrigeration cabinet, thereby reducing the chances of mistakes made during installation of the tubing.